Method and system for introduction of an active material to a chemical process

ABSTRACT

A method and system of for introducing an active material to a chemical process in which a processing element including a passive component and an active element is installed within the system and exposed to a chemical process performed within the system. As the chemical process proceeds, the passive component erodes and thereby exposes the active component embedded therein. The introduction of the active component to the chemical process alters the chemical process.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. application Ser. No.10/673,376, filed on Sep. 30, 2003 now abandoned, the entire content ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and system for introducing anactive material to a chemical process, and, more particularly, to amethod and system for the introduction of the active material in orderto tailor the chemical process for optimal performance.

2. Description of the Related Art

The fabrication of integrated circuits (IC) in the semiconductorindustry typically employs plasmas to create and assist surfacechemistry within a plasma reactor to remove material from and depositmaterial to a substrate. In general, plasmas are formed within theplasma reactor under vacuum conditions by heating electrons to energiessufficient to sustain ionizing collisions with a supplied process gas.Moreover, the heated electrons can have energy sufficient to sustaindissociative collisions. Therefore, a specific set of gases underpredetermined conditions (e.g., chamber pressure, gas flow rate, etc.)are chosen to produce a population of charged species and chemicallyreactive species suitable to the particular process being performedwithin the chamber (e.g., etching processes where materials are removedfrom the substrate or deposition processes where materials are added tothe substrate). While it is known that certain materials introduced intothe processing chamber during the plasma process can affect or enhancethe process performed in the chamber, the mechanisms for delivery ofsuch materials into the process chamber are complex and expensive.

Although the formation of a population of charged species (ions, etc.)and chemically reactive species is necessary for performing the functionof the plasma processing system (i.e., material etch, materialdeposition, etc.) at the substrate surface, other component surfaces onthe interior of the processing chamber are exposed to the physically andchemically active plasma environment and, in time, can erode. Theuncontrolled erosion of exposed components in the plasma processingsystem can lead to a gradual degradation of the plasma processingperformance, can contribute contamination to the plasma processing, and,in general, is such that erosion of these components affects specificprocesses in the plasma processing system. Thus, the semiconductorindustry has primarily focused on monitoring and controlling the erosionof exposed components in a plasma processing system.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a method and systemfor introducing an active material into a chemical process in asemiconductor manufacturing process.

Another object of the present invention is to utilize the erosion ofexposed components in a processing chamber to improve a processperformed in the chamber.

Yet another object of the present invention is to utilize controllederosion of exposed components in a processing chamber to introduce anactive material into the semiconductor manufacturing process.

Accordingly, in one aspect of the present invention a processing elementis configured to affect a chemical process in a semiconductormanufacturing system. The processing element including a passivecomponent configured to be coupled to a semiconductor manufacturingsystem and configured to erode when exposed to a chemical process in thesemiconductor manufacturing system. The processing element includes anactive component coupled to the passive component and configured toalter the chemistry of the chemical process when the active component isexposed to the chemical process.

In another aspect of the present invention, a semiconductormanufacturing system for processing a substrate using a chemical processincludes a processing chamber configured to facilitate the chemicalprocess, a substrate holder coupled to the processing chamber andconfigured to support the substrate; a gas distribution system coupledto the processing chamber and configured to introduce a process gas tothe processing chamber; a plasma source coupled to the processingchamber and configured to generate a plasma in the processing chamber,and at least one processing element coupled to at least one of theprocessing chamber, the substrate holder, the gas distribution system,and the plasma source. The at least one processing element includes apassive component configured to erode when exposed to the chemicalprocess in the semiconductor manufacturing system, and includes anactive component coupled to the passive component and configured toalter the chemistry of the chemical process when the active component isexposed to the chemical process.

In another aspect of the present invention, a method of utilizing aprocessing element to affect a chemical process in a semiconductormanufacturing system includes installing in a semiconductormanufacturing system at least one processing element, including apassive component configured to be coupled to the semiconductormanufacturing system and including an active component coupled to thepassive component, exposing the at least one processing element to thechemical process in order to facilitate erosion of the passive element,and introducing the active component during the erosion of the passivecomponent in order to alter the chemistry of the chemical process whenthe active component is exposed to the chemical process.

In a further aspect of the present invention, the method monitors theerosion of the yet passive component.

In still a further aspect of the present invention, the method controlsthe introduction of the active component by (1) varying a distributionof at least one of a size, composition, and a concentration of theactive component in the passive component, (2) varying the temperatureof the passive component, or (3) tailoring a geometry of the passivecomponent.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present invention and many attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic depicting a semiconductor manufacturing systemaccording to a preferred embodiment of the present invention;

FIG. 2 is a schematic depicting a semiconductor manufacturing systemaccording to one embodiment of the present invention;

FIG. 3 is a schematic depicting a semiconductor manufacturing systemaccording to another embodiment of the present invention;

FIG. 4 is a schematic depicting a semiconductor manufacturing systemaccording to a further embodiment of the present invention;

FIG. 5 is a schematic depicting a semiconductor manufacturing systemaccording to one embodiment of the present invention;

FIG. 6A is a cross-sectional view of a processing element according toone embodiment of the present invention;

FIG. 6B is a cross-sectional view of an eroded processing element suchas that depicted in FIG. 6A;

FIG. 7A is a cross-sectional view of a cylindrical processing elementaccording to one embodiment of the present invention;

FIG. 7B is an exploded view of an inner surface of a processing elementof the present invention;

FIG. 7C is a schematic illustrating the temporal variation of thesurface area of the inner surface of the processing element depicted inFIG. 7B during erosion;

FIG. 7D is an exploded view of an inner surface of yet anotherprocessing element of the present invention;

FIG. 7E is a schematic illustrating a temporal variation of the surfacearea of the inner surface of the processing element depicted in FIG. 7Dduring erosion; and

FIG. 8 depicts a method of utilizing a processing element to affect achemical process in a semiconductor manufacturing system according toone embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

As noted in the Description of Related Art section above, existingmechanisms for delivery of process affecting materials into a plasmaprocess chamber are complex and expensive. For example, while some solidmaterials may be used to enhance a chemical process performed in aprocessing chamber, there is currently no tested mechanism for deliveryof the solid material into the process chamber during the chemicalprocess. Moreover, the introduction of a process affecting liquidmaterials into a semiconductor manufacturing system is a generally atenuous process. A liquid material introduced to the chamber willfrequently condensed on walls below a temperature at which the liquidwill vaporize, resulting in an extended “memory effect” on thesemiconductor manufacturing process. Further, in vacuum processingsystems, evaporation of the condensed liquid cools the liquid resultingin at best a reduced evaporation rate and at worse the liquid beingfrozen into a solid phase. Finally, vacuum processing pumps do nottypically handle pumping large quantities of liquid with somedegradation. Thus, traditional processes for injecting liquids orinjecting a pre-vaporized liquids into a semiconductor manufacturingsystem, especially a vacuum processing system, do not provide acontrolled mechanism for reliably providing the liquid material.

Although the erosion of exposed components in a chemical processingsystem has generally been perceived by the semiconductor manufacturingindustry as a problem to be controlled, the present inventors havediscovered that controlled erosion of chamber components can be used asa mechanism for delivery of process affecting materials into the processchamber. In particular, one embodiment of the present inventionincorporates a liquid as an active material in an inert matrix as thepassive material as part of a chamber component such that the activematerial be released upon exposure and erosion of the chamber componentby a chemical process (e.g., a plasma process). This embodiment of theinvention provides the active material in a controlled fashion at apoint of use and consumption where it will impact the chemical processand be less likely to negatively affect the semiconductor processingsystem.

Referring now to the drawings, wherein like reference numerals designateidentical, or corresponding parts throughout the several views, and moreparticularly to FIG. 1, a semiconductor manufacturing system 1 isdepicted in FIG. 1 including a processing chamber 10, a plasma source 15coupled to the processing chamber 10 and configured to generate a plasmain a processing region 5 in the processing chamber 10, a substrateholder 20 coupled to the processing chamber 10 and configured to supporta substrate 25, a process gas distribution system 40 coupled to theprocessing chamber 10 and configured to introduce process gas toprocessing region 5, and a pumping system 45 coupled to the processingchamber 10 and configured to alter the pressure of processing region 5in processing chamber 10. For example, processing chamber 10 canfacilitate processing substrate 25 at an elevated pressure, atatmospheric pressure, or at a reduced (vacuum) pressure. Moreover, forexample, processing chamber 10 can facilitate the use of a plasma toperform a dry plasma etch process, wherein a pattern formed in a masklayer (such as a pattern formed in a light-sensitive layer usingmicro-lithography) is transferred to an underlying film on substrate 25.The semiconductor manufacturing system 1 can be configured to processvarious substrates (e.g., 100 mm, 125 mm, 150 mm, 200 mm, 300 mmdiameter substrates, or larger).

Referring again to FIG. 1, the semiconductor manufacturing system 1further includes one or more processing elements 50 coupled to theprocessing chamber 10. Additionally, the one or more processing elements50 includes one or more exposed surfaces that are exposed to or are incontact with a chemical process in processing region 5. The one or moreprocessing elements 50 can, for example, constitute a process unit thatcan be periodically replaced wholly, or part-by-part. At least one ofthe one or more processing elements 50 includes a passive component andat least one active component. The active component is configured toaffect a change in the chemistry upon exposure to the chemical process.For example, the active component can provide at least one of reactionpromotion, reaction inhibition, creation of a protective skin on afeature, polymer strengthening, and polymer weakening. Any one of theabove provisions can affect the etching profile control during, forexample, dry plasma etching of a feature in substrate 25.

According to the illustrated embodiment of the present inventiondepicted in FIG. 2, the semiconductor manufacturing system 1 includesprocessing chamber 10, substrate holder 20, upon which a substrate 25 tobe processed is affixed, gas injection system 40, and vacuum pumpingsystem 45. Substrate 25 can be, for example, a semiconductor substrate,a wafer, or a liquid crystal display (LCD). Processing chamber 10 canbe, for example, configured to facilitate the generation of plasma inprocessing region 5 adjacent a surface of substrate 25. A plasma isformed within processing chamber 10 via collisions between heatedelectrons and an ionizable gas. An ionizable gas or mixture of gases isintroduced via gas injection system 40, and the process pressure isadjusted. Desirably, the plasma is utilized to create materials specificto a predetermined materials process, and to aid either the depositionof material to substrate 25 or the removal of material from the exposedsurfaces of substrate 25. Controller 55 can be used to control vacuumpumping system 45 and gas injection system 40.

Substrate 25 can be, for example, transferred into and out of theprocessing chamber 10 through a slot valve (not shown) and chamberfeed-through (not shown) via robotic substrate transfer system where thesubstrate 25 is received by substrate lift pins (not shown) housedwithin substrate holder 20 and mechanically translated by devices housedtherein. Once substrate 25 is received from substrate transfer system,substrate 25 can be placed on an upper surface of substrate holder 20.

For example, substrate 25 can be affixed to the substrate holder 20 viaan electrostatic clamping system 28. Furthermore, substrate holder 20can further include a cooling system including a re-circulating coolantflow that receives heat from substrate holder 20 and transfers heat to aheat exchanger system (not shown), or when heating, transfers heat fromthe heat exchanger system. Moreover, a gas (e.g., He or H₂ gas) can bedelivered to the back-side of the substrate via a backside gas system 26to improve the gas-gap thermal conductance between substrate 25 andsubstrate holder 20. Such a system can be utilized when temperaturecontrol of the substrate is required at elevated or reducedtemperatures. For example, temperature control of the substrate can beuseful at temperatures in excess of the steady-state temperatureachieved due to a balance of the heat flux delivered to the substrate 25from the plasma and the heat flux removed from substrate 25 byconduction to the substrate holder 20. In other embodiments, heatingelements, such as resistive heating elements, or thermo-electricheaters/coolers can be included.

As shown in FIG. 2, substrate holder 20 includes an electrode throughwhich RF power is coupled to plasma in processing region 5. For example,substrate holder 20 can be electrically biased at an RF voltage via thetransmission of RF power from RF generator 30 through impedance matchnetwork 32 to substrate holder 20. The RF bias can serve to heatelectrons to form and maintain the plasma. In one configuration, thesystem can operate as a reactive ion etch (RIE) reactor, where thechamber and upper gas injection electrode serve as ground surfaces. Atypical frequency for the RF bias can range from 1 MHz to 100 MHz and ispreferably 13.56 MHz.

Alternately, RF power can be applied to the substrate holder electrodeat multiple frequencies. Furthermore, impedance match network 32 servesto maximize the transfer of RF power to plasma in processing chamber 10by minimizing reflected power. Various match network topologies (e.g.,L-type, π-type, T-type, etc.) and automatic control methods can beutilized.

With continuing reference to FIG. 2, a process gas can be, for example,introduced to processing region 5 through gas injection system 40.Process gas can, for example, include a mixture of gases such as argon,CF_(4′) and O₂, or argon, C₄F₈ and O₂ for oxide etch applications, orother chemistries such as, for example, O₂/CO/Ar/C₄F₈, O₂/CO/Ar/C₅F₈,O₂/CO/Ar/C₄F₆, O₂/Ar/C₄F₆, N₂/H₂. Gas injection system 40 includes ashowerhead where a process gas is supplied from a gas delivery system(not shown) to the processing region 5 through for example a gasinjection plenum (not shown), a series of baffle plates (not shown), anda multi-orifice showerhead gas injection plate (not shown).

Vacuum pump system 45 can, for example, include a turbo-molecular vacuumpump (TMP) capable of a pumping speed up to 5000 liters per second (andgreater) and a gate valve for throttling the chamber pressure. Inconventional dry plasma etch process, a 1000 to 3000 liter per secondTMP is generally employed. Furthermore, a device for monitoring chamberpressure (not shown) is coupled to the process chamber 10. The pressuremeasuring device can be, for example, a Type 628B Baratron absolutecapacitance manometer commercially available from MKS Instruments, Inc.(Andover, Mass.).

Additionally, semiconductor manufacturing system 1 can include aplurality of sensors coupled to processing chamber 10 to measure dataand controller 55 can be coupled to the sensors to receive the data. Thesensors can include both sensors that are intrinsic to the processingchamber 10 and sensors that are extrinsic to the processing chamber 10.Sensors intrinsic to processing chamber 10 include those sensorspertaining to the functionality of processing chamber 10 such as forexample the measurement of the Helium backside gas pressure, heliumbackside flow, electrostatic clamping (ESC) voltage, ESC current,substrate holder 20 temperature (or lower electrode (LEL) temperature),coolant temperature, upper electrode (UEL) temperature, forward RFpower, reflected RF power, RF self-induced DC bias, RF peak-to-peakvoltage, chamber wall temperature, process gas flow rates, process gaspartial pressures, chamber pressure, capacitor settings (i.e., C₁ and C₂positions), a focus ring thickness, RF hours, focus ring RF hours, andany statistic thereof. Sensors extrinsic to processing chamber 10include those sensors not directly related to the functionality ofprocessing chamber 10 such as for example a light detection device 34for monitoring the light emitted from the plasma in processing region 5as shown in FIG. 2, or an electrical measurement device 36 formonitoring the electrical system of processing chamber 10 as shown inFIG. 2.

The light detection device 34 can include a detector such as a (silicon)photodiode or a photomultiplier tube (PMT) for measuring the total lightintensity emitted from the plasma. The light detection device 34 canfurther include an optical filter such as a narrow-band interferencefilter. In an alternate embodiment, the light detection device 34includes a line CCD (charge coupled device) or CID (charge injectiondevice) array and a light dispersing device such as a grating or aprism. Additionally, light detection device 34 can include amonochromator (e.g., grating/detector system) for measuring light at agiven wavelength, or a spectrometer (e.g., with a rotating grating) formeasuring the light spectrum such as, for example, the device describedin U.S. Pat. No. 5,888,337, the entire contents of which areincorporated by reference.

The light detection device 34 can include a high resolution opticalemission spectrometer (OES) sensor from Peak Sensor Systems. Such an OESsensor has a broad spectrum that spans the ultraviolet (UV), visible(VIS), and near infrared (NIR) light spectrums. The resolution isapproximately 1.4 Angstroms, that is, the sensor is capable ofcollecting 5550 wavelengths from 240 to 1000 nm. The sensor is equippedwith high sensitivity miniature fiber optic UV-VIS-NIR spectrometerswhich are, in turn, integrated with 2048 pixel linear CCD arrays.

The spectrometers receive light transmitted through single and bundledoptical fibers, where the light output from the optical fibers isdispersed across the line CCD array using a fixed grating. Similar tothe configuration described above, light emitting through an opticalvacuum window is focused onto the input end of the optical fibers via aconvex spherical lens. Three spectrometers, each specifically tuned fora given spectral range (UV, VIS and NIR), form a sensor for a processchamber. Each spectrometer includes an independent A/D converter. Andlastly, depending upon the sensor utilization, a full emission spectrumcan be recorded every 0.1 to 1.0 seconds.

The electrical measurement device 36 can include, for example, a currentand/or voltage probe, a power meter, or spectrum analyzer. For example,plasma processing systems often employ RF power to form plasma, in whichcase, an RF transmission line, such as a coaxial cable or structure, isemployed to couple RF energy to the plasma through an electricalcoupling element (i.e., inductive coil, electrode, etc.). Electricalmeasurements using, for example, a current-voltage probe, can beexercised anywhere within the electrical (RF) circuit, such as within anRF transmission line. Furthermore, the measurement of an electricalsignal, such as a time trace of voltage or current, permits thetransformation of the signal into frequency space using discrete Fourierseries representation (assuming a periodic signal). Thereafter, theFourier spectrum (or for a time varying signal, the frequency spectrum)can be monitored and analyzed to characterize the state of semiconductormanufacturing system 1. A voltage-current probe can be, for example, adevice as described in detail in pending U.S. application Ser. No.60/259,862 filed on Jan. 8, 2001, and U.S. Pat. No. 5,467,013, theentire contents of which is incorporated herein by reference.

In alternate embodiments, electrical measurement device 36 can include abroadband RF antenna useful for measuring a radiated RF field externalto semiconductor manufacturing system 1. One broadband antenna suitablefor the present invention is the commercially available broadband RFantenna, Antenna Research Model RAM-220 (0.1 MHz to 300 MHz).

In general, the plurality of sensors can include any number of sensors,intrinsic and extrinsic, which can be coupled to processing chamber 10to provide tool data to the controller 55.

Controller 55 includes a microprocessor, memory, and a digital I/O port(potentially including D/A and/or A/D converters) configured to generatecontrol voltages sufficient to communicate and activate inputs to thesemiconductor manufacturing system 1 as well as monitor outputs fromsemiconductor manufacturing system 1. As shown in FIG. 2, process toolcontroller 55 can be coupled to and exchange information with RFgenerator 30, impedance match network 32, gas injection system 40,vacuum pump system 45, backside gas delivery system 26, electrostaticclamping system 28, light detection device 34, and electricalmeasurement device 36. A program stored in the memory is utilized tointeract with the aforementioned components of a semiconductormanufacturing system 1 according to a stored process recipe. One exampleof controller 55 is a DELL PRECISION WORKSTATION 530™, available fromDell Corporation, Austin, Tex. Controller 55 can be locally locatedrelative to the semiconductor manufacturing system 1, or controller 55can be remotely located relative to the semiconductor manufacturingsystem 1. For example, controller 55 can exchange data withsemiconductor manufacturing system 1 using at least one of a directconnection, an intranet, and the internet. Controller 55 can be coupledto an intranet at, for example, a customer site (i.e., a device maker,etc.), or controller 55 can be coupled to an intranet at, for example, avendor site (i.e., an equipment manufacturer). Additionally, forexample, controller 55 can be coupled to the Internet. Furthermore,another computer (i.e., controller, server, etc.) can, for example,access controller 55 to exchange data via at least one of a directconnection, an intranet, and the internet.

As shown in FIG. 3, semiconductor manufacturing system 1 can include amagnetic field system 60. For example, the magnetic field system 60 canbe a stationary, or either a mechanically or electrically rotating DCmagnetic field in order to potentially increase plasma density and/orimprove material processing uniformity. Moreover, controller 55 can becoupled to magnetic field system 60 in order to regulate the fieldstrength or speed of rotation.

As shown in FIG. 4, the semiconductor manufacturing system 1 can includean upper electrode 70. For example, RF power can be coupled from RFgenerator 72 through impedance match network 74 to upper electrode 70. Afrequency for the application of RF power to the upper electrodepreferably ranges from 10 MHz to 200 MHz and is preferably 60 MHz.Additionally, a frequency for the application of power to the lowerelectrode can range from 0.1 MHz to 30 MHz and is preferably 2 MHz.Moreover, controller 55 can be coupled to RF generator 72 and impedancematch network 74 in order to control the application of RF power toupper electrode 70.

As shown in FIG. 5, the semiconductor manufacturing system 1 of FIG. 1can include an inductive coil 80. For example, RF power can be coupledfrom RF generator 82 through impedance match network 84 to inductivecoil 80, and RF power can be inductively coupled from inductive coil 80through dielectric window (not shown) to plasma processing region 45. Afrequency for the application of RF power to the inductive coil 80preferably ranges from 10 MHz to 100 MHz and is preferably 13.56 MHz.Similarly, a frequency for the application of power to the substrateholder 20 preferably ranges from 0.1 MHz to 30 MHz and is preferably13.56 MHz. In addition, a slotted Faraday shield (not shown) can beemployed to reduce capacitive coupling between the inductive coil 80 andplasma. Moreover, controller 55 can be coupled to RF generator 82 andimpedance match network 84 in order to control the application of powerto inductive coil 80. In an alternate embodiment, inductive coil 80 canbe a “spiral” coil or “pancake” coil in communication with the plasmaprocessing region 45 from above as in a transformer coupled plasma (TCP)reactor.

Alternately, the plasma can be formed using electron cyclotron resonance(ECR). In yet another embodiment, the plasma is formed from thelaunching of a Helicon wave. In yet another embodiment, the plasma isformed from a propagating surface wave.

Referring now to FIG. 6A, a cross-sectional view of processing element50 is illustrated. Processing element 50 includes a passive component100 and an active component 110. For example, the passive component 100can be an inert binding medium that is designed to bind, or embed, theactive component 110. As processing element 50 erodes in time asillustrated in FIG. 6B, the active component 110 can become exposed tothe chemical process, such as a plasma, and hence becomes active in thechemical composition of the chemical process of for example the plasma.

The passive component 100 includes in one embodiment of the presentinvention a binding medium that may, for example, include a solid suchas a polymer, a porous polymer, or a foam, or it may, for example,include a non-Newtonian fluid such as a gel. The active component 110can be a material either in solid form, such as a powder or smallparticles, or in liquid form. In one example, when the active component110 includes small particles, the passive component 100 can be apolymer. The small particles may be dispersed within a polymer such asKAPTON, polyimide, ultem, amorphous carbon, TEFLON, Peek, thermoplasticpolymer, thermoset polymer, or sol-gel, ceramic, or glass. For example,U.S. Pat. No. 4,997,862, the entire contents of which are incorporatedby reference, describes a process for preparing a mixture of colloidalparticles in a resin matrix. Alternatively, in another example, when theactive component 110 is a liquid additive, the passive component 100 canbe a porous polymer, or a foam. For example, U.S. Pat. No. 6,436,426,the entire contents of which are incorporated by reference, describes aprocess for producing porous polymer materials. The active component 110being in this embodiment of the present invention injected into thepores of the passive component 100.

Thus, an embodiment of the present invention provides a mechanism forinexpensive and effective delivery of solid or liquid active material toa chemical process performed in a process chamber. Moreover, anembodiment of the present invention provides a way of utilizing thewidely perceived problem of erosion of chamber components to actuallyenhance a chemical process performed in the process chamber.

Further, in one embodiment, the active component 110 includesorgano-metallic compounds, such as those compounds formed using yttrium,aluminum, iron, titanium, zirconium, and hafnium, and mixtures thereof.Some non-limiting examples of specific organo-metallic compounds for usein the present invention are yttrium tris hexafluoroacetylacetonate,yttrium tris(2,2,6,6-hexamethyl)-3,5-heptanedionate, yttrium trisdiphenylacetylacetonate, 1,2-diferrocenylethane, aluminumtris(2,2,6,6-tetramethyl)-3-5-heptanedionate, aluminum lactate,aluminum-8-hydroxyquinoline, bis(cyclopentadienyl)titanium pentasulfide,bis(pentamethylcyclopentadienyl) hafnium dichloride, zirconiumacetylacetonate, zirconium tetra(2,26,6-tetramethyl)-3,5-pentanedionate,zirconium tetra(1,5-diphenylpentane-2-4-dione), ferrocene aldehyde,ferrocene methanol, ferrocene ethanol, ferrocene carboxylic acid,ferrocene dicarboxylic acid, 1,2 diferrocene ethane, 1,3 diferrocenepropane, 1,4 diferrocene butane and decamethylferrocene. According to anembodiment of the present invention the addition of organo-metalliccompounds as the active component 110 leads to greater etch resistancefor a photoresist. Additionally, these additives can alter loadingeffects of the plasma, and subsequent deposition reactions, and canimprove a center-to-edge uniformity and an aspect ratio dependentetching (i.e., an isolated-to-nested array structure uniformity).

In another embodiment, the active component 110 includes ultraviolet(UV) absorbers and stabilizers, such as benzophenone, benzotriazole, andhindered amine stabilizers (HALS). According to an embodiment of thepresent invention, the addition of UV absorbers/stabilizers as activecomponent 110 can lead to reduced bond-breaking in photoresist duringplasma etching and, therefore, less photoresist damage and greater etchresistance. Additionally, these additives can be used to alter loadingeffects of the plasma, and subsequent deposition reactions, and canimprove a center-to-edge uniformity and an aspect ratio dependentetching (i.e., an isolated-to-nested array structure uniformity).

In another embodiment, the active component 110 includes antioxidants,such as hindered phenols, aromatic amines, organophosphorous compounds,thiosynergists, hydroxylamine, lactones, and acrylated bis-phenols.According to an embodiment of the present invention, the addition ofanti-oxidants can tie up free radicals, thereby leading to moredeposition and different bonding structures within a depositionchemistry, leading to less photoresist damage, greater etch resistance,and increased selectivity. Additionally, these additives can be used toalter loading effects of the plasma, and subsequent depositionreactions, and can improve a center-to-edge uniformity and an aspectratio dependent etching such as an isolated-to-nested array structureuniformity. For example, isolated versus nested array structure suggeststhe spacing between structures (or pitch), wherein for isolatedstructures the spacing is large, and for nested structures, the spacingis small.

In order to control the rate at which the active component 110 isexposed to the processing plasma, at least one of a process gas, aprocessing element temperature, a geometry of the processing element, asize of the active component, a concentration of the active component,or a distribution of the active component is adjusted, according to anembodiment of the present invention. For example, the size of thechamber component and the orientation of the active component coupledthereto may be configured in consideration of a known erosion rate ofthe chamber component in a particular chamber chemical process. As wouldbe appreciated by one of ordinary skill in the art, differentconfigurations of the chamber component may be used in consideration offactors such as the active component composition, the process in thechamber, the composition of the passive matrix, etc.

As another example of controlling the rate of the active component, aprocess gas can include an etch gas having one or more constituents, anyof which can be adjusted by introduction of an active component toaffect the chemistry of the chemical process and, in turn affect theinteraction between the chemistry and the active component 110. Forinstance, when etching oxide dielectric films such as silicon oxide,silicon dioxide, etc., or when etching inorganic low-k dielectric filmssuch as oxidized organosilanes, the etch gas composition generallyincludes a fluorocarbon-based chemistry such as at least one of C₄F₈,C₅F₈, C₃F₆, C₄F₆, CF₄, etc., and at least one of an inert gas, oxygen,and CO. According to an embodiment of the present invention, theabove-noted organo-metallic compounds can be encapsulated in theabove-noted passive porous polymer matrix, e.g. Teflon. Upon heating thepassive matrix, the organo-metallic compounds are expected to bereleased to the plasma process due to the accelerated consumption of thepassive component, hence, affecting for example the electron-energy,electron distribution, and thus uniformity of the dielectric etchingprocess.

Alternatively, for example, when etching organic low-k dielectric filmssuch as SiLK-I, SiLK-J, SiLK-H, SiLK-D, and porous SiLK semiconductordielectric resins commercially available from Dow Chemical, and FLARE™and Nano-glass commercially available from Honeywell, the etch gascomposition generally includes at least one of a nitrogen-containinggas, and a hydrogen-containing gas. Alternatively, for instance, whenetching silicon, the etch gas composition generally includes at leastone of a fluorine containing gas such as NF₃, SiF₄, or SF₆, HBr, and O₂.As before, the encapsulation of an organo-metallic compound in forexample a porous polymer are expected to upon for example heatingintroduce the organo-metallic compounds into the plasma etching processand improve uniformity.

Indeed, the temperature of the processing element can be varied toaffect the rate at which the active component 110 is introduced into theplasma chemistry. The processing element can be heated passively, due toits contact with the chemical process, or the processing element can beheated actively by a voltage-controlled heating element disposed in theprocessing chamber proximate the processing element. For instance, theheating element can be a resistive heating element such as a tungsten,nickel-chromium alloy, aluminum-iron alloy, aluminum nitride, etc.,filament. Examples of commercially available materials to fabricateresistive heating elements include KANTHAL, NIKROTHAL, AKROTHAL, whichare registered trademark names for metal alloys produced by KANTHALCorporation of Bethel, Conn. The KANTHAL family includes ferritic alloys(FeCrAl) and the NIKROTHAL family includes austenitic alloys (NiCr,NiCrFe). When an electrical current flows through the filament, power isdissipated as heat. Hence, the use of a temperature control unit,coupled to the heating element in the processing chamber, can adjust orcontrol the temperature of the processing element and thus control arate of delivery of the active material to the chemical process. In oneexample, the temperature control unit can include a controllable DCpower supply such as a Firerod cartridge heater commercially availablefrom Watlow (1310 Kingsland Dr., Batavia, Ill., 60510).

Alternately, for example, the cross-sectional geometry of the processingelement can be varied in order to affect the amount of surface areaexposed to the processing plasma as a function of time. FIG. 7A shows across-sectional view of processing element 50, wherein FIG. 7B and FIG.7D present two alternatives for the geometrical shape of the exposedsurface 150. In FIG. 7B, the exposed surface 50 is the cylindrical innersurface of processing element 50 as depicted in FIG. 7A. As theprocessing element erodes radially outward, the exposed surface areaincreases with time (by redial erosion outwards) as shown in FIG. 7C.Alternatively, in FIG. 7D, the exposed surface 150 includes a groovestructure formed on the cylindrical inner surface of processing element50 in FIG. 7A. As the processing element 50 erodes radially outward, theexposed surface area remains substantially constant with time (orerosion) as shown in FIG. 7E.

In one embodiment of the present invention, at least one of the size(pore size or particle size) of the active component and theconcentration of the active component (pores or particles) are variedspatially throughout the processing element in order to affect theamount the active component 110 is exposed to the processing plasma intime. Further, in one embodiment of the present invention, thedistribution of the active component (pores or particles) can varyspatially throughout the processing element in order to affect theamount the active component 110 is exposed to the processing plasma intime. For example, as the processing element erodes, the concentrationof the active component 110 can increase, decrease, or remain constantin order to counter the effects of a drifting process betweencleaning/maintenance intervals within the processing chamber.

Accordingly, in one method according to an embodiment of the presentinvention, a processing element is utilized to affect a chemical processin a semiconductor manufacturing system is described. This methodfollows the steps depicted in FIG. 8 by flowchart 200, beginning in step210, with providing a processing element in a semiconductormanufacturing system. As described above, the processing elementincludes a passive component configured to erode when the activecomponent is exposed to the chemical process in the semiconductormanufacturing system, and includes an active component coupled to thepassive component and configured to alter the chemistry of the chemicalprocess when the active component is exposed to the chemical process.The passive component includes a material that when introduced to thechemical process is inert. For example, the passive component can be apolymer, a porous polymer, a foam, or a gel. The active componentincludes a material that when introduced to the chemical process, altersthe chemistry of the process to the extent that the processing of asubstrate is affected. For example, the active component can be anorgano-metallic compound, an ultraviolet (UV) absorber, or anantioxidant to affect photoresist patterning and development on asubstrate.

In step 220, the processing element is exposed to the chemical processin the semiconductor manufacturing system. The semiconductormanufacturing system can be any one of the processing systems describedin FIGS. 1 through 5. Therein, the processing element can be coupled toat least one of the processing chamber, the gas distribution system,substrate holder, or the plasma source. For example, in a dry plasmaetch system, the chemical process is initiated by introducing a processgas within the processing chamber, and igniting a plasma using theplasma source. Thereafter, the chemical process proceeds, and interactswith the exposed processing element.

In step 230, the active component is introduced to the chemical processas the passive component erodes in the presence of the chemical process.

Optionally, in step 240, the method monitors the processing element inorder to determine the effectiveness of the introduction of the activecomponent to the chemical process. For example, during plasmaprocessing, the processing element can be monitored by measuring theintensity of light emitted from the processing chamber, wherein changesin the light intensity can correspond to changes in the introduction ofthe active component to the chemical process. Moreover, the spectrum oflight across a pre-determined spectral range can be monitored usingoptical emission spectroscopy (OES), such as the system described above,to detect changes corresponding to the introduction of the activecomponent. Monitoring light emission and using the light emission fordetecting changes in a plasma process are well known to those skilled inthe art optical diagnostics for plasma monitoring.

Optionally, for example, the processing element can be monitored bymeasuring a thickness of the processing element and detecting a changein the thickness as the chemical process proceeds. The thickness can bemeasured using an ultrasonic sensor, such as that described in U.S. Pat.No. 6,019,000 (Stanke et al.; Sensys Instruments Corporation, The Boardof Trustees of the Leland Stanford Junior University), the entirecontents of which is incorporated herein by reference.

Optionally, during plasma processing, the processing element can bemonitored by measuring a voltage (or current) at a point within theelectrical system using a voltage-current probe, such as the systemdescribed above. The voltage (or current) can be measured within thetransmission line extending from an impedance match network to therespective electrode through which RF power is coupled to the processingplasma (see FIGS. 2 through 5). Since the processing element exists aspart of the overall electrical system, due in part to its electricalconnection to the processing plasma, a change in the processing element(i.e., due to erosion) translates into a change in the electricalimpedance for the electrical system, and can be detected as a change inthe voltage (or current), or a harmonic thereof of the applied voltage,if the RF power is maintained a constant (via the RF generator andimpedance match network).

Optionally, in step 250, the method controls the rate at which theactive component is introduced to the chemical process. At least one ofa process gas, a processing element temperature, a geometry of theprocessing element, a size of the active component, a concentration ofthe active component, or a distribution of the active componentdetermines the rate of introduction of the active component. Forexample, after the monitoring system detects a first level of activecomponent introduced to the chemical process, then the rate ofintroduction of the active component can be increased or decreased toachieve a second level of active component introduced to the chemicalprocess by increasing or decreasing the temperature of the processingelement, respectively.

Although only certain exemplary embodiments of this invention have beendescribed in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention.

Hence, numerous modifications and variations of the present inventionare possible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described herein.

The invention claimed is:
 1. A processing element for a semiconductor manufacturing system, said processing element comprising: a cylindrical unit including a passive polymeric component and an active component; said cylindrical unit having a first radially-extending surface and a second radially extending surface opposite the first radially-extending surface, wherein an inside diameter of the cylindrical unit forms an opening for disposition of the cylindrical unit around a substrate position in the semiconductor manufacturing system and the second radially extending surface is a substantially planar surface for disposition on a substrate holder in the semiconductor manufacturing system; said passive polymeric component configured to erode when exposed to a plasma process in said semiconductor manufacturing system; and said active component including a liquid component embedded within a part of said passive component and configured to alter the chemistry of the processing when exposed to the plasma process.
 2. The processing element as recited in claim 1, wherein said active component comprises an organo-metallic compound.
 3. The processing element as recited in claim 2, wherein said organo-metallic compound comprises at least one of yttrium, aluminum, iron, titanium, zirconium, and hafnium.
 4. The processing element as recited in claim 2, wherein said organo-metallic compound comprises at least one of yttrium tris hexafluoroacetylacetonate, yttrium tris(2,2,6,6-hexamethyl)-3,5-heptanedionate, yttrium tris diphenylacetylacetonate, 1,2-diferrocenylethane, aluminum tris(2,2,6,6-tetramethyl)-3-5-heptanedionate, aluminum lactate, aluminum-8-hydroxyquinoline, bis(cyclopentadienyl)titanium pentasulfide, bis(pentamethylcyclopentadienyl)hafnium dichloride, zirconium acetylacetonate, zirconium tetra(2,26,6-tetramethyl)-3,5-pentanedionate, zirconium tetra(1,5-diphenylpentane-2-4-dione), ferrocene aldehyde, ferrocene methanol, ferrocene ethanol, ferrocene carboxylic acid, ferrocene dicarboxylic acid, 1,2 diferrocene ethane, 1,3 diferrocene propane, 1,4 diferrocene butane and decamethylferrocene.
 5. The processing element as recited in claim 1, wherein said active component comprises an ultraviolet (UV) absorber.
 6. The processing element as recited in claim 5, wherein said UV absorber comprises at least one of benzophenone, benzotriazole, and hindered amine stabilizers (HALS).
 7. The processing element as recited in claim 1, wherein said active component comprises an antioxidant.
 8. The processing element as recited in claim 7, wherein said antioxidant comprises at least one of hindered phenols, aromatic amines, organophosphorous compounds, thiosynergists, hydroxylamine, lactones, and acrylated bis-phenols.
 9. The processing element as recited in claim 1, wherein said active component further comprises a distribution of solid particles encapsulated within said passive component.
 10. The processing element as recited in claim 9, wherein said distribution of solid particles within said passive component comprises variations in at least one of a particle size, a particle composition, and a particle concentration.
 11. The processing element as recited in claim 1, wherein said processing element is configured to be temperature controlled in order to alter a rate at which said active component is exposed to said plasma process.
 12. The processing element as recited in claim 1, wherein said processing element is configured geometrically to affect a rate at which said active component is exposed to said plasma process.
 13. The processing element as recited in claim 1, wherein said processing element is cylindrical, and an inner surface of said processing element comprises, a groove structure formed thereon and configured to expose a substantially constant surface area of said inner surface as said inner surface recedes during erosion by said plasma process.
 14. The processing element as recited in claim 1, wherein said passive component comprises at least one of a polymer, a porous polymer, a foam, and a gel.
 15. The processing element as recited in claim 14, wherein said polymer comprises a polyimide.
 16. A semiconductor manufacturing system for processing a substrate using a plasma process, comprising: a processing chamber configured to facilitate said plasma process; a substrate holder coupled to said processing chamber and configured to support said substrate; a gas distribution system coupled to said processing chamber and configured to introduce a process gas to said processing chamber; a plasma source coupled to said processing chamber and configured to generate a plasma in said processing chamber; at least one processing element coupled to at least one of said processing chamber, said substrate holder, said gas distribution system, and said plasma source; and said at least one processing element comprising, a cylindrical unit including a passive polymeric component and an active component, said cylindrical unit having a first radially-extending surface and a second radially extending surface opposite the first radially-extending surface, wherein an inside diameter of the cylindrical unit forms an opening for disposition of the cylindrical unit around a substrate position in the semiconductor manufacturing system and the second radially extending surface is a substantially planar surface for disposition on a substrate holder in the semiconductor manufacturing system, said passive polymeric component configured to erode when exposed to a plasma process in said semiconductor manufacturing system, and said active component including a liquid component embedded within a part of said passive component and configured to alter the chemistry of the processing when exposed to the plasma process.
 17. The semiconductor manufacturing system as recited in claim 16, wherein said active component comprises an organo-metallic compound.
 18. The semiconductor manufacturing system as recited in claim 17, wherein said organo-metallic compound comprises at least one of yttrium, aluminum, iron, titanium, zirconium, and hafnium.
 19. The semiconductor manufacturing system as recited in claim 17, wherein said organo-metallic compound comprises at least one of yttrium tris hexafluoroacetylacetonate, yttrium tris(2,2,6,6-hexamethyl)-3,5-heptanedionate, yttrium tris diphenylacetylacetonate, 1,2-diferrocenylethane, aluminum tris(2,2,6,6-tetramethyl)-3-5-heptanedionate, aluminum lactate, aluminum-8-hydroxyquinoline, bis(cyclopentadienyl)titanium pentasulfide, bis(pentamethylcyclopentadienyl)hafnium dichloride, zirconium acetylacetonate, zirconium tetra(2,26,6-tetramethyl)-3,5-pentanedionate, zirconium tetra(1,5-diphenylpentane-2-4-dione), ferrocene aldehyde, ferrocene methanol, ferrocene ethanol, ferrocene carboxylic acid, ferrocene dicarboxylic acid, 1,2 diferrocene ethane, 1,3 diferrocene propane, 1,4 diferrocene butane and decamethylferrocene.
 20. The semiconductor manufacturing system as recited in claim 16, wherein said active component comprises at least one of an organo-metallic compound, an ultraviolet absorber, and an antioxidant.
 21. The semiconductor manufacturing system as recited in claim 16, wherein said active component further comprises a distribution of solid particles encapsulated within said passive component.
 22. The semiconductor manufacturing system as recited in claim 21, wherein said distribution of solid particles within said passive component comprises varieties in at least one of a particle size, a particle composition, and a particle concentration.
 23. The semiconductor manufacturing system as recited in claim 16, wherein said processing element is configured to be temperature controlled in order to alter a rate at which said active component is exposed to said plasma process.
 24. The semiconductor manufacturing system as recited in claim 16, wherein said at least one processing element is configured geometrically to affect a rate at which said active component is exposed to said plasma process.
 25. The semiconductor manufacturing system as recited in claim 16, wherein said passive component comprises at least one of a polymer, a porous polymer, a foam, and a gel. 